Cyclohexane derivatives



United States 3,100,205 CYCLOHEXANE DERIVATIVES Karl Schulte, Darmstadt, Heinrich Miiller, Pfungstadt, near Darmstadt, and Hans-Giinther Kraft, Darmstadt, Germany, assignors to E. Merck Aktiengesellschaft, Darmstadt, Germany, a corporation of Germany No Drawing. Filed May 11, 1961, Ser. No. 109,255 8 Claims. (Cl. 260-2472) This invention relates to derivatives of cyclohexane. More particularly, it is directed to cyclohexane derivatives of the following Formula I as well as their salts and quaternary ammonium compounds:

4 5 3 6 1 2 CHE-N RE R R4 in which R =pheny1, cyclohexyl or cyclohexenyl, which radicals may be substituted one or two times by halogen, OH, alkyl having at most 2. C-atoms, alkoxy having at most 3 C-atoms, or O-CH O,

CHEN R =alkyl having at most 8 C-atoms,

R and R =hydrogen, alkyl having at most 4 C-atoms or alkyl having at most 4 C-atoms which are connected with each other by CH or N,

R =H, alkoxy having at most 2 C-atoms, alkyl having at most 4 C-atoms, phenyl,

R =H, OH, alkoxy having at most 4 C-atoms, alkanoyl- *oxy having at most 10 C-atoms, in which connection R and R may also together represent =0, =N-OH or ethylenedioxy,

R and R are H, alkyl having at most 6 C-atoms, hy-

droxy alkyl having at most 3 C-atoms, which alkyl radicals may be bound with each other -via CH 0 or N.

It has been found that the cyclohexane derivatives of the above Formula I as well as their salts and quaternary ammonium compounds develop an excellent cough-relieving action.

The new compounds of this invention can be prepared in a variety of ways. One can:

(a) React a cyclohexanone, which is disubstituted in 4-position, of Formula II:

in which R and R have the significance indicated above,

3,100,205 Patented Aug. 6, 1963 ice in which R and R have the significance indicated above.

This Mannich condensation is advantageously carried out in aqueous-alcoholic solution; the ketoue, the aqueous formaldehyde solution and the amine component being heated with the addition of acid. One can also proceed in the following manner: one mol of the ketone is reacted with about 1.1 to 1.2 mols of formaldehyde in aqueous solution and about 1.1 mols of an acid addition salt of the amine component. It may possibly be advisable, prior to the actual Mannich condensation, to prepare the oxymethylene compound from the formaldehyde and the amine and then to use it in the reaction with the ketone. lnstead of an aqueous formaldehyde solution, panaformaldehyde or the trimeric form of formaldehyde in alcoholic, and preferably water-free alcoholic solution, can also be used. As the amine component, there may be used, in addition to ammonia, for instance, the following secondary or primary amines or their acid addition salts. Methylamine, ethyliamine, n-propylamine, nor iso-butylamine, dimethylamine, diethylamine, di-n-propylamine, di-n-butylamine, ethylmethylamine, ethylbutyl-amine, piperidine, morphol ine, thiomorpholine, N-methylpiperazine, pyrrolidine, etc.

In the Mannich condensation, there is obtained a ketone of the general Formula IV:

1 2 cHPN R t") (IV) be hydrogenated in the presence of ordinary catalysts such as Raney nickel and in the presence of a solvent such as methanol, preferably under normal conditions or elevated pressure, for instance at 6' atmospheres gauge, as well as elevated temperature, to form the corresponding secondary alcohol. The carbonyl group of the compound of the Formula IV can also be converted into a corresponding tertiary alkyl group by reaction with organometallic compounds, for instance with Grignard compounds or alkali metal alkyls. The Grignard reaction can for instance be carried out in such manner that the ethereal solution of the ketone of Formula IV is added, drop by drop, preferably with cooling, to an ethereal Gn'guard solution and thereupon the reaction mixture is heated under reflux until the reaction is complete. The hydroxyl group obtained upon a treatment with organometallic compounds or upon hydrogenation from the carbonyl group can thereupon be esteriiied or etherified by customary methods. For example, the resultant alcohol can be esterified with an acid halide or anhydride in asuitablesolvent, such as toluene, as well as in the presence-of anagentwhich combinesw-ith acid, such as pyridine or potassium carbonate. The etherification of the hydroxyl group can take place via the sodium compound which is reacted with reactive organic halides, for instance, with ethyl iodide or benzy-l chloride.

The new cyclohexane derivatives can, in accordance with the present invention, furthermore be prepared by ordinary hydrogenation of a nitrile of Formula V:

inwhich R to-R have the significance indicated above.

The nitrile groupof Compound V is in this connection converted either into an amino-methyl group or a sub stituted amin-methyl group, depending-on the reaction conditions applied. If one operates under the customary hydrogenation conditions, for instance, with hydrogen in the presence of Raney nickel, the amin-methyl group is obtained; If the analogous hydrogenation is carried out in, the presenceof an amine of Formula HI, there is obtained directly an amino-methyl group substituted with the radicals R and R Such hydrogenations are preferably carried out under elevated pressure and possibly at elevatedtemperature. As solvents, there is used, for instance, an alcohol such as methanol or a hydrocarbon such as cyclohexane, etc.

'Ihenitrile of Formula V required as starting material can for instance, be prepared by a-halogenation of a hetone ofFormula II, followed bythe reaction of the resultantZ-halogen ketone with alkali cyanide. A nitrile of Eqrmula V can also be prepared from a 'y,'y-disubstitutedpimelic acid dinitrile by ring closureby the Ziegler method. In this case, there is obtained the l-imino compound corresponding to the nitrile -V in which the radicals li and-R represent a =NH-group, which =NH can thereupon be hydrolyzed by customary methods to form the carbonyl group.

1(d) In accordance with the invention, the new cyclohexane derivatives can also be obtained by replacing the substituent X of a cyclohexane derivative of Formula VI:

Ra- R4 inww hich R' to R have the significance indicated above,

. and'X'isOH, C1 or Br, by an N group u 4 derivatives consists, in accordance with the invention, in reducing the CO-groupof an acid amide of Formula VII:

in which R to R 'have the significance indicated above.

The reduction is advantageously efiected by complex metal hydrides such as lithium aluminum hydride. The organo metal lic complexes which are firstrtorrned in this connection are thereupon decomposed in customary manner with water or chloride. As solvent tor the reaction, diethyl ether, tetrahydrofuran or dioxane can, for instance, the used. If an unprotected car-bonyl group is present'in l-position, it is converted by the complex metal hydride into a secondary hydroxyl group. It is therefore advisable, if the carbonyl group is to be retained, toprotect it from the reaction, for instance, by ketalizing. Upon the decomposition of the metal hydride which then takes place, acid conditions must be avoided if the ketal group is to be retained. On the other hand, one can regenerate the canhonyl group during the acid decomposition and thus produce a compound of Formula I in which the substituents R and R together constitute oxygen.

The acid amides of FormulaVIl, can be prepared by known methods from esters of the following \Formula VH1:

in which Y is an ester group, by reaction with an amine.

(f) In accordance with the invention, it is nurthermore possible to convert a compound of Formula I by known methods into the corresponding acid additionsalt, fOT instance, by treatment with hydrochloric acid or hydrobromic acid, acetic acid, tartaric acid, fumaric acid, maleic acid, citric acid, ascorbic acid, caproic acid, propionic acid, etc.

It is also possible toquaternize the nitrogen of a compound of Formula I by customary methods, as forinstance, by treatment with al'kyl halides.

The preparation of acid addition saltsis particularly advantageous when water-soluble compounds suitable for injection purposes are to be prepared.

The compounds obtained in accordance with the invention have excellent cough-relieving properties- There have been found/to be particularly etfective those compounds of Formula I in which R is phenyl or cyclohexenyl, R is an ester group, R is hydrogen, R is O-acyl and R and R together with nitrogen, constitute a morpholine or piperidine radical.

In accordance with the invention, for example, the following final products or theiracid-addition and quaternary salts can be obtained:

2-morpholinomethyl-4 carbomethoxy-4-phenyl-cyclohexane-l-one-hydrochlon'de,

2-pyrrolidinomethyl-4-carhomethoxy-4-phenyl-cyclohexane-l-one,

Z-piperidinomethyi-l-carboruethoxy-4-phenyl-cyclohexane-l-one-hydro'chloxide,

2-octahydroindolinomethyl-4-carbomethoxy-4-phenyl-cyclohexane-l-one-hydrobromide,

Z-diethylaminomethyl-4-carbomethoxy-4-phenyl-cyclohexane-l-one-hydrochloride,

2-piperidinomethyl-4-carbomethoxy-4-phenyl-cyclohexane-l-ol,

2morpholinomethy-l-4acarbomethoxy-4phenyl-cyclohexane-l-ol.

(Z-piperidinomethyll-carb omethoxy-4-phenyl) -cyclohexyl-l-acetate,

( 21morpholinomethyl-4-canb omethoxy-4-phenyl) -cyclo hexyl-l-acetate,

( 2-morpho1inomethyl-4-carb ornethoxy-4-phenyl) -cyclohexyl-l-propionate,

(2-morpholinomethyl-4-carbomethoxy-4-cyclohexenyl)- 'cyclohexyl-l-propionate,

2-morpholinomethyl-4-phenyl-4-ca.rbo-octyloxy4cyclohexyl-l-acetate,

2-piperidinomethyl-4-phenyl-4-carbobutyloxy-cyclohexyllpropionate,

2-piperidinomethyl-4-cyclohexenyl-4-carbobutyloxycyclohexyl-l-acetate,

2-rnorpholinomethyl-4-(3,4'-dimethoxyphenyl)-4-carbomethoxy-cyclohexane-l-ol,

2-morpholinomethyl-4 3 ,4'-dimethoxyphenyl) -4-carb omethoxy-cyclohexyl-l-propionate.

The new cyclohexane derivatives obtained in accordance with the invention were tested as to their coughrelieving action by the method of Konzett and Rothlin (Experientia, vol. 10, page 472 (1954). In comparative tests, it was found that the new compounds are superior in their action to known cough-relieving agents. Thus, for instance, the 2-piperidinomethyl-4-carbomethoxy-4-phenyl-cyclohexyl-1-acetate obtained in accordance with the invention and the 2-morpholinomethyl-4- carbomethoxy 4 phenyl cyclohexane 1 one hydrochloride are 3 times more effective than Z-dimethylamino- 4-cyano-4-phenyl-5-methyl-hexaue-citrate. The 2-octahydroindolinomethyl 4 carbomethoxy 4 phenyl cyclohexane-l-one-hydrobromide prepared in accordance with the invention exhibited 1.5 times the cough-relieving action of piperidinoethoxyethyl thiophenyl-pyridylamino-(l)carboxylate, while the 2-pyrrolidinomethyl-4- carbomethoxy 4 phenyl cyclohexane 1 one showed 3 times the cough-relieving action thereof. The Z-piperidino methyl 4 :carbomethoxy 4 phenyl cyclohex- .ane-l-ol obtained in accordance with the method of the invention and the also unknown 2-diethylaminomethy1-4- carbomethoxy-4-phenyl-cyclohexane-1-one hydrochloride had twice as strong a cough-relieving action as l-pheny-l-lo-chloropheny1-3-dimethylamino-propanol- 1 hydrochloride. It was furthermore found that among the new compounds obtained in accordance with the invention, the Z-dimethylamino-methy-l 4 carb omethoxy 4 phenyl-cyclohexyl 1 acetate, 2 piperidinomethyl-4-cyano-4-pheny1- cyclohexane-l-one and 2-piperidinornethyl-4-carbomethoxy-4-phenyl-cyclohexane-l-one-hydrochloride develop a cough-relieving effect which is -2.5 to 3.5 times greater than that of 1,1-diphenyl-Z-piperidino-propanol-l.

One important advantage of the new substances is particularly that they are not habit-forming and do not exert any action on the circulation. The use of the new compounds in human medicine is therefore considerably less dangerous than the use of compounds of the codeine type.

The new substances can be worked into all forms of preparations customary for pharmaceutical purposes, for instance, pills, dragees, tablets, emulsions, solutions, injection solutions, inhalation sprays, etc., can be prepared therefrom.

The following are examples in accordance with this invention:

Example 1 23.3 grams of 4-phenyl-4-carbomethoxy-cyclohexanel-one, 17 grams of 35% aqueous formaldehyde and 9 grams of dimethylamino-hydrochloride are heated for 4 hours under reflux in 300 cc. of alcohol. The solvent is evaporated and the residue is treated with 50 cc. of

2 N-hydrochloric acid and extracted with ether. The aqueous phase is made alkaline with caustic soda solution while cooling and then exhaustively extracted with ether. After the drying and evaporation of the solvent, there is obtained Z-dim-ethylaminomethyl-4-phenyl-4- carbomethoxy-cyclohexane-l-one. The base can be converted into the hydrochloride of a melting point of 158 to 160 C. by customary methods.

Example 2 16 grams of 2-dimethylaminomethyl-4-carbomethoxy- 4-phenyl4cyclohexane-l-one-hydrochloride are dissolved in 600 cc. of water, and the solution is shaken with 1 gram of pre-reduoed platinum oxide under hydrogen until 0.05 mol of hydrogen have been absorbed. The solvent is thereupon substantially evaporated, the residue made alkaline and extracted with ether. After drying and evaporation of the solvent, there is obtained Z-dimethylaminomethyl 4 :carbomethoxy 4 phenyl cyclohexane-l-ol, B.P. 157/0.2 mm. Hg. The hydrochloride prepared therefrom by customary methods melts at 199 to 200 C. M.P. of the 3,5-dinitro-benzoate: 250 C.

Example 3 6.6 grams of 2-dimethylaminornethyl-4-phenyl-4-carbomethoxy-cyolohexanol-hydrochloride are dissolved in 50 cc. of chloroform and heated for 2 hours under reflux with 1.6 grams of acetylchloride and 1.6 grams of pyridine. The residue remaining after the evaporation of the solvent is dissolved in a small amount of water, the solution is made alkaline with caustic soda solution and exhaustively extracted with ether. The residue remaining after the evaporation of the ether is recrystallized from 8 cc. of absolute alcohol. There is obtained 2-dimethylaminomethyl 4 phenyl 4 carbomethoxy cyclohexyl-l-acetate of a melting point of 93 to 94 C.

Example 4 7.4 grams of 2-morpholinomethyl-4-carbomethoxy-4- phenyl-cyclohexane-Lone-hydrochloride are dissolved in 50 cc. of glacial acetic acid and shaken with 0.5 gram of prewreduced platinum oxide under hydrogen until 0.08 mol of H have been absorbed. Thereupon the solvent is removed and the residue is treated with dilute caustic soda solution and extracted with ether. After drying and evaporation of the ether, there is obtained 2morpholinomethyl 4 carbomethoxy 4 cyclohexyl cyclohexanel-ol of a M.P. of 104 to 105 C. The hydrochloride prepared by customary methods melts at 172 to 173 C. (from isopropanol) Example 5 2.96 grams of Z-piperidi-nomethyl-4-cyano-4-phenylcyclohexane-l-one are dissolved in 30 cc. of 1 N-hydrochloric acid and shaken with 0.5 gram of pre-reduced platinum oxide in 20 cc. of water under hydrogen until 0.03 mol H have been absorbed. The solution is made alkaline with caustic soda solution and extracted with ether. After drying and evaporation of the solvent, there is obtained 2 piperidinomethyl-4 aminomethyl-4-phenylcyclohexane-l-ol of an M.P. of 104 C.; hydrochloride M.P. 152 C.

Example 6 To a Grignard solution prepared from 17.2 grams of monobromobenzene in 100 cc. of ether, there is added, drop by drop, at room temperature, a solution of 20.3 grams of 2-dimethylaminomethyl-4-phenyl-4-cyano-cyclohexanone in 50 cc. of ether. After the addition has been completed, heating is effected for one hour under reflux. The cooled reaction mixture is poured into 300 cc. of ice water and treated with cc. of 25% ammonium chloride solution and 16 cc. of concentrated ammonium hydroxide solution. Exhaustive extraction With other is thereupon effected followed with drying over sodium sulfate whereupon the solvent is evaporated. There is ob- 13 In accordance with the foregoing methods, the following compounds can, likewise, be prepared:

4-(para-propoxy)phenyl 4 carbomethoxy 2 dimethylammo-methyl-cyclohexane-l-one 1,1-diethoxy-2-dimethylaminomethyl 4 phenyl-4-carbomethoxy-cyclohexane 1-butyl-2-piperidinomethyl-4-pheny1-4-cyano-cyc1ohexane- 1-01 1,4-diphenyl-2-dimethylaminomethyl 4 cyano-cyclohexane-l-ol (Z-dimethylaminomethyl 4 phenyl 4 carbomethoxy)- cyclohexyl-caprinate 2 dimethylaminomethyl-4-phenyl-4-carbomethoxy-cyclohexane-l-one-propylene ketal Z-N-hexyl-N-methylaminomethy1-4-phenyl-4-cyanocyclohexaned-one 2 dimeflhylaminomethyl-4-phenyl-4-carbobenzoxy-cyclohexane-l-one 2-piperidinomethy1-4-phenyl 4 N butyl-amino-methylcyclohexane-l-ol 2-dimethylaminomethyl-4-phenyl 4 morpholino-m'ethylcyclohexane 1-one 2 -dimethy1aminomethyl 4 phenyl-4-piperidine-methylcyclohexane-l-one It will be understood that the foregoing description of the invention and the examples set forth are merely i1lus trative of the principles thereof. Accordingly, the appended claims are to be construed as defining the invention Within the full spirit and scope thereof.

We claim: 1. 2-piperidinomethyl 4 carbomethoxy -4-phenylcycylohexane l-one-hydrochloride.

2. 2-pipe1idinomethyl-4-carbomethoxy 4 phenylcycylohexane l-ol.

3. (2 piperidinomethyl-4-carbomethoxy-4-phenyl)-cyclohexanol-1-acetate.

4. 2 morpholinomethyl-4-phenyl-4-carboctoxy-cyclohexanol-l-acetate.

5. 2 piperidinomethy1-4-pheny1-4-carbobutoxy-cyclohexanol-1-propionate.

6. 2 morpholinomethyl-4-(3',4'-dimethoxypheny1)-4- carbomethoxy-cyclohexane-1-ol.

7. 2 morpholinomethyl-4-(3',4'-dimethoxyphenyl)-4- carbomethoxy-cyclohexanol-l-propionate.

8. A compound selected from the group consisting of: (1) a compound having the formula (2) The pharmaceu-tically acceptable acid addition salts thereof, and

(3) the quaternary ammonium compounds thereof wherein the quaternizing moiety is a member of the group consisting of alkylchloride and alkylbromide each having a maximum of 8 carbon atoms; and

wherein:

R designates a member of the group consisting of phenyl, cyclohexyl, cyclohexenyl, and monoand di-substituted phenyl whereof the substituent is a member of the group consisting of bromine, hydroxyl, alkyl having at most 4 carbon atoms, alkoxy having a maximum of 3 carbon atoms, and methylene dioxy;

R designates a member of the group consisting of CHZNHC O 0 R7, and

wherein:

R designates an alkyl having a maximum of 8 carbon atoms;

R and R designate a member of the group consisting of hydrogen and alkyl having a maximum of 4 carbon atoms;

R and R when linked together, jointly with the nitrogen atom, form a member selected from the group consisting of piperidino, morpholino, and piperazino;

R designates a member of the group consisting of 'hydrogen, alkoxy having a maximum of 2 carbon atoms, alkyl having a maximum of 4 carbon atoms, and phenyl;

R designates a member of the group consisting of hydrogen, hydroxyl, alkoxy having a maximum of 4 carbon atoms and alkanoyloxy having a maximum of 10 carbon atoms;

R and R jointly designate a member of the group consisting of =0, =NOH, and ethylenedioxy;

R and R designate a member of the group consisting of hydrogen, alkyl having a maximum of 6 carbon atoms, and hydroxyalkyl having a maximum of 3 carbon atoms; and when linked together, jointly constitute with the nitrogen atom a member of the group consisting of pyrrolidino, piperidino, morpholino, and N'-methyl-piperazmo. 

4. 2 - MORPHOLINOMETHYL-4-PHENYL-4-CARBOCTOXY-CYCLOHEXANOL-1-ACETATE.
 8. A COMPOUND SELECTED FROM THE GROUP CONSISTING OF: (1) A COMPOUND HAVING THE FORMULA 